Organic electroluminescent materials and devices

ABSTRACT

A compound having a structure of Formula I: 
     
       
         
         
             
             
         
       
     
     is provided. In the structure of Formula I, each one of X 1  to X 16  is independently CR X  or N; each R X  and R are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene, azadibenzofuran, azadibenzothiophene, azadibenzoselenophene, triphenylene, azatriphenylene, and combinations thereof; and any adjacent R X  can join to form fused or unfused rings. Formulations and devices, such as an OLEDs, that include the compound containing a structure of Formula I are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Patent Application Ser. No.62/192,628, filed Jul. 15, 2015, the entire contents of which isincorporated herein by reference.

PARTIES TO A JOINT RESEARCH AGREEMENT

The claimed invention was made by, on behalf of, and/or in connectionwith one or more of the following parties to a joint universitycorporation research agreement: The Regents of the University ofMichigan, Princeton University, University of Southern California, andthe Universal Display Corporation. The agreement was in effect on andbefore the date the claimed invention was made, and the claimedinvention was made as a result of activities undertaken within the scopeof the agreement.

FIELD

The present invention relates to compounds for use in devices, such asorganic light emitting diodes, including the same.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting diodes/devices (OLEDs), organic phototransistors, organicphotovoltaic cells, and organic photodetectors. For OLEDs, the organicmaterials may have performance advantages over conventional materials.For example, the wavelength at which an organic emissive layer emitslight may generally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Alternatively the OLED can be designed to emit white light. Inconventional liquid crystal displays emission from a white backlight isfiltered using absorption filters to produce red, green and blueemission. The same technique can also be used with OLEDs. The white OLEDcan be either a single EML device or a stack structure. Color may bemeasured using CIE coordinates, which are well known to the art.

One example of a green emissive molecule is tris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the following structure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processable” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

SUMMARY

According to one embodiment, a compound having a structure of Formula I:

is provided. In the structure of Formula I:

each one of X¹ to X¹⁶ is independently CR^(X) or N;

each R^(X) and R are independently selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole,azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene,azadibenzofuran, azadibenzothiophene, azadibenzoselenophene,triphenylene, azatriphenylene, and combinations thereof; and

any adjacent R^(X) can join to form fused or unfused rings.

According to another embodiment, a first organic light emitting deviceis provided. The first organic light emitting device can include ananode; a cathode; and an organic layer disposed between the anode andthe cathode. The organic layer can include a compound of Formula I asdescribed herein. The device can be incorporated into a consumerproduct, an electronic component module, an organic light-emittingdevice, and/or a lighting panel.

According to yet another embodiment, a formulation containing a compoundof Formula I as described herein is provided.

BRIEF DESCRIPTION OP THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIGS. 3 & 4 are tables summarizing photophysic and electrochemistry datafor selected compounds of Formula I.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998; (“Baldo-”)and Baldo et al., “Very high-efficiency green organic light-emittingdevices based on electrophosphorescence,” Appl. Phys. Lett., vol. 75,No. 3, 4-6 (1999) (“Baldo-II”), are incorporated by reference in theirentireties. Phosphorescence is described in more detail in U.S. Pat. No.7,279,704 at cols. 5-6, which are incorporated by reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and OVJD. Othermethods may also be used. The materials to be deposited may be modifiedto make them compatible with a particular deposition method. Forexample, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processability than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentinvention may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material.In one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the invention canbe incorporated into a wide variety of electronic component modules (orunits) that can be incorporated into a variety of electronic products orintermediate components. Examples of such electronic products orintermediate components include display screens, lighting devices suchas discrete light source devices or lighting panels, etc. that can beutilized by the end-user product manufacturers. Such electroniccomponent modules can optionally include the driving electronics and/orpower source(s). Devices fabricated in accordance with embodiments ofthe invention can be incorporated into a wide variety of consumerproducts that have one or more of the electronic component modules (orunits) incorporated therein. Such consumer products would include anykind of products that include one or more light source(s) and/or one ormore of some type of visual displays. Some examples of such consumerproducts include flat panel displays, computer monitors, medicalmonitors, televisions, billboards, lights for interior or exteriorillumination and/or signaling, heads-up displays, fully or partiallytransparent displays, flexible displays, laser printers, telephones,cell phones, tablets, phablets, personal digital assistants (PDAs),wearable device, laptop computers, digital cameras, camcorders,viewfinders, micro-displays, 3-D displays, vehicles, a large area wall,theater or stadium screen, or a sign. Various control mechanisms may beused to control devices fabricated in accordance with the presentinvention, including passive matrix and active matrix. Many of thedevices are intended for use in a temperature range comfortable tohumans, such as 18 degrees C. to 30 degrees C., and more preferably atroom temperature (20-25 degrees C.), but could be used outside thistemperature range, for example, from −40 degree C. to +80 degree C.

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The term “halo,” “halogen,” or “halide” as used herein includesfluorine, chlorine, bromine, and iodine.

The term “alkyl” as used herein contemplates both straight and branchedchain alkyl radicals. Preferred alkyl groups are those containing fromone to fifteen carbon atoms and includes methyl, ethyl, propyl,1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl,1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl,1,2-dimethylpropyl, 2,2-dimethylpropyl, and the like. Additionally, thealkyl group may be optionally substituted.

The term “cycloalkyl” as used herein contemplates cyclic alkyl radicals.Preferred cycloalkyl groups are those containing 3 to 10 ring carbonatoms and includes cyclopropyl, cyclopentyl, cyclohexyl, adamantyl, andthe like. Additionally, the cycloalkyl group may be optionallysubstituted.

The term “alkenyl” as used herein contemplates both straight andbranched chain alkene radicals. Preferred alkenyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkenyl groupmay be optionally substituted.

The term “alkynyl” as used herein contemplates both straight andbranched chain alkyne radicals. Preferred alkynyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkynyl groupmay be optionally substituted.

The terms “aralkyl” or “arylalkyl” as used herein are usedinterchangeably and contemplate an alkyl group that has as a substituentan aromatic group. Additionally, the aralkyl group may be optionallysubstituted.

The term “heterocyclic group” as used herein contemplates aromatic andnon-aromatic cyclic radicals. Hetero-aromatic cyclic radicals also meansheteroaryl. Preferred hetero-non-aromatic cyclic groups are thosecontaining 3 to 7 ring atoms which includes at least one hetero atom,and includes cyclic amines such as morpholino, piperdino, pyrrolidino,and the like, and cyclic ethers, such as tetrahydrofuran,tetrahydropyran, and the like. Additionally, the heterocyclic group maybe optionally substituted.

The term “aryl” or “aromatic group” as used herein contemplatessingle-ring groups and polycyclic ring systems. The polycyclic rings mayhave two or more rings in which two carbons are common to two adjoiningrings (the rings are “fused”) wherein at least one of the rings isaromatic, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl,heterocycles, and/or heteroaryls. Preferred aryl groups are thosecontaining six to thirty carbon atoms, preferably six to twenty carbonatoms, more preferably six to twelve carbon atoms. Especially preferredis an aryl group having six carbons, ten carbons or twelve carbons.Suitable aryl groups include phenyl, biphenyl, triphenyl, triphenylene,tetraphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, and azulene, preferably phenyl,biphenyl, triphenyl, triphenylene, fluorene, and naphthalene.Additionally, the aryl group may be optionally substituted.

The term “heteroaryl” as used herein contemplates single-ringhetero-aromatic groups that may include from one to five heteroatoms.The term heteroaryl also includes polycyclic hetero-aromatic systemshaving two or more rings in which two atoms are common to two adjoiningrings (the rings are “fused”) wherein at least one of the rings is aheteroaryl, e.g., the other rings can be cycloalkyls, cycloalkenyls,aryl, heterocycles, and/or heteroaryls. Preferred heteroaryl groups arethose containing three to thirty carbon atoms, preferably three totwenty carbon atoms, more preferably three to twelve carbon atoms.Suitable heteroaryl groups include dibenzothiophene, dibenzofuran,dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene,benzoselenophene, carbazole, indolocarbazole, pyridylindole,pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole,oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine,pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine,indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole,benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline,quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine,phenazine, phenothiazine, phenoxazine, benzofuropyridine,furodipyridine, benzothienopyridine, thienodipyridine,benzoselenophenopyridine, and selenophenodipyridine, preferablydibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole,indolocarbazole, imidazole, pyridine, triazine, benzimidazole,1,2-azaborine, 1,3-azaborine, 1,4-azaborine, borazine, and aza-analogsthereof. Additionally, the heteroaryl group may be optionallysubstituted.

The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group,aryl, and heteroaryl may be unsubstituted or may be substituted with oneor more substituents selected from the group consisting of deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

As used herein, “substituted” indicates that a substituent other than His bonded to the relevant position, such as carbon. Thus, for example,where R¹ is mono-substituted, then one R¹ must be other than H.Similarly, where R¹ is di-substituted, then two of R¹ must be other thanH. Similarly, where R¹ is unsubstituted, R¹ is hydrogen for allavailable positions.

The “aza” designation in the fragments described herein, i.e.aza-dibenzofuran, aza-dibenzothiophene, etc. means that one or more ofthe C—H groups in the respective fragment can be replaced by a nitrogenatom, for example, and without any limitation, azatriphenyleneencompasses both dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. Oneof ordinary skill in the art can readily envision other nitrogen analogsof the aza-derivatives described above, and all such analogs areintended to be encompassed by the terms as set forth herein.

It is to be understood that when a molecular fragment is described asbeing a substituent or otherwise attached to another moiety, its namemay be written as if it were a fragment (e.g. phenyl, phenylene,naphthyl, dibenzofuryl) or as if it were the whole molecule (e.g.benzene, naphthalene, dibenzofuran). As used herein, these differentways of designating a substituent or attached fragment are considered tobe equivalent.

Tetrabenzoazonine has a unique saddle-shaped structure in which all thephenyl groups are orientated above and below the average plane of themolecule and have minimum conjugation. With this distinct structure, ithas been discovered that tetrabenzoazonine is very useful as a hightriplet N-containing building block for many applications, e.g., OLEDmaterials.

According to one embodiment, a compound having a structure of Formula I:

Formula I is described. In the structure of Formula I:

each one of X¹ to X¹⁶ is independently CR^(X) or N;

each R^(X) and R are independently selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole,azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene,azadibenzofuran, azadibenzothiophene, azadibenzoselenophene,triphenylene, azatriphenylene, and combinations thereof; and

any adjacent R^(X) can join to form fused or unfused rings.

In some embodiments, the compound has the structure of Formula I-a:

Formula I-a. In the structure of Formula I-a:

each one of R¹ to R¹⁶ independently represents a substituent selectedfrom the group consisting of hydrogen, deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof,

any adjacent R¹-R¹⁶ can join to form a fused or unfused ring.

In some embodiment, the compound has a structure of Formula II:

Formula II. In the structure of Formula II,

n is an integer≧1;

R^(t) is

all rings are optionally independently substituted by a substituentselected from the group consisting of deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; and

any adjacent substituents can join to form fused or unfused rings.

In some embodiments, compounds of Formula II are selected from the groupconsisting of

where all of the rings are optionally substituted. In some suchembodiments, none of the rings of Compounds II-1 through II-6 aresubstituted. In some such embodiments, one or more rings of CompoundsII-1 through II-6 are independently substituted by a substituentselected from the group consisting of deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; where any adjacentsubstituents can join to form fused or unfused rings.

In some embodiments, R is selected from the group consisting of aryl,heteroaryl, substituted aryl, and substituted heteroaryl. In some suchembodiments, the compound is selected from the group consisting of:

where all of the rings are optionally substituted. In some suchembodiments, none of the rings of Compounds III-a-1 through III-a-23 aresubstituted. In some such embodiments, one or more rings of CompoundsIII-a-1 through III-a-23 are independently substituted by a substituentselected from the group consisting of deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; where any adjacentsubstituents can join to form fused or unfused rings.

In some embodiments, a compound of Formula I-a is disclosed where atleast one of R¹ to R¹⁶ is selected from the group consisting of aryl,heteroaryl, substituted aryl, and substituted heteroaryl. In some suchembodiments, the compound is selected from the group consisting of:

where all of the rings are optionally substituted. In some suchembodiments, none of the rings of Compounds III-1b-1 through III-b-18are substituted. In some such embodiments, one or more rings ofCompounds III-b-1 through III-b-18 are independently substituted by asubstituent selected from the group consisting of deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,axatriphenylene, and combinations thereof: where any adjacentsubstituents can join to form fused or unfused rings.

In some embodiments, a compound of Formula I-a is described where R is atriarylamine containing group (i.e. a substituent containing atriarylamine group). In some such embodiments, the compound is selectedfrom the group consisting of:

where all of the rings are optionally substituted. In some suchembodiments, none of the rings of Compounds IV-1 through IV-4 aresubstituted. In some such embodiments, one or more rings of CompoundsIV-1 through IV-4 are independently substituted by a substituentselected from the group consisting of deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; where any adjacentsubstituents can join to form fused or unfused rings.

In some embodiments, a compound of Formula I-a is described where R is agroup containing at least one electron withdrawing group of CN, F,C_(m)F_(2m+1), Si_(m)F_(2m+1), NCO, NCS, OCN, SCN, OC_(m)F_(2m+1), orSC_(m)F_(2m+1), wherein m≧1. In some such embodiments, the compound isselected from the group consisting of

and Compound V-34; where R^(e) is CN, F, C_(m)F_(2m+1), Si_(m)F_(2m+1),NCO, NCS, OCN, SCN, OC_(m)F_(2m+1), or SC_(m)F_(2m+1), and m≧1; andwhere R^(t) is

In one embodiment, R^(e) is CN. In such an embodiment, the compound isselected from the group consisting of:

In these embodiments, all rings of R^(t) are optionally independentlysubstituted by a substituent selected from the group consisting ofdeuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole,azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene,azadibenzofuran, azadibenzothiophene, azadibenzoselenophene,triphenylene, azatriphenylene, and combinations thereof; and anyadjacent substituents on R^(t) can join to form fused or unfused rings.

In some embodiments, a compound of Formula I-a is described where R is agroup containing pyrimidine or triazene. In some such embodiments, thecompound is selected from the group consisting of:

where R^(t) is

In some such embodiments, all rings of R^(t) are optionallyindependently substituted by a substituent selected from the groupconsisting of deuterium, halogen, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, carbazole, azacarbazole, dibenzofuran, dibenzothiophene,dibenzoselenophene, azadibenzofuran, azadibenzothiophene,azadibenzoselenophene, triphenylene, azatriphenylene, and combinationsthereof; and any adjacent substituents on R^(t) can join to form fusedor unfused rings.

In some embodiments, at least one of X¹ to X¹⁶ is N. In some suchembodiments, the compound is selected from the group consisting of:

where all of the rings are optionally substituted. In some suchembodiments, none of the rings of Compounds VII-1 through VII-14 aresubstituted. In some such embodiments, one or more rings of CompoundsVII-1 through VII-14 are independently substituted by a substituentselected from the group consisting of deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; where any adjacentsubstituents can join to form fused or unfused rings.

In some embodiments, at least two of adjacent R¹-R¹⁵ are fused into or

where Z is CR′R″, NR′, O, S, or Se. In such embodiments, R′ and R″ areindependently selected from the group consisting of hydrogen, deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole,azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene,azadibenzofuran, azadibenzothiophene, azadibenzoselenophene,triphenylene, azatriphenylene, and combinations thereof; and all of therings are optionally substituted. In some such embodiments, the compoundis selected from the group consisting of:

wherein all of the rings are optionally substituted. In some suchembodiments, none of the rings of Compounds VIII-1 through VIII-22 aresubstituted. In some such embodiments, one or more rings of CompoundsVIII-1 through VIII-22 are independently substituted by a substituentselected from the group consisting of deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; where any adjacentsubstituents can join to form fused or unfused rings.

According to another embodiment, a first organic light emitting deviceis described. The first organic light emitting device can include ananode; a cathode; and an organic layer disposed between the anode andthe cathode. The organic layer can include a compound having thestructure of Formula I, and its variants, as described herein.

In some embodiments, the organic layer is an emissive layer and thecompound of Formula I is a host.

In some embodiments, the organic layer also includes a phosphorescentemissive dopant wherein the phosphorescent emissive dopant is atransition metal complex having at least one ligand or part of theligand if the ligand is more than bidentate, selected from the groupconsisting of:

In the structures of the ligands:

each X¹ to X¹³ are independently selected from the group consisting ofcarbon and nitrogen;

X is selected from the group consisting of BR′, NR′, PR′, O, S, Se, C═O,S═O, SO₂, CR′R″, SiR′R″, and GeR′R″;

R′ and R″ are optionally fused or joined to form a ring;

each R_(a), R_(b), R_(c), and R_(d) may represent from mono substitutionto the possible maximum number of substitution, or no substitution;

R′, R″, R_(a), R_(b), R_(c), and R_(d) are each independently selectedfrom the group consisting of hydrogen, deuterium, halogen, alkyl,cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl,alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl,carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof; and

any two adjacent substituents of R_(a), R_(b), R_(c), and R_(d) areoptionally fused or joined to form a ring or form a multidentate ligand.

In some embodiments, the organic layer is a charge carrier blockinglayer and the compound of Formula I is a charge carrier blockingmaterial in the organic layer.

In some embodiments, the organic layer is a charge carrier transportinglayer and the compound of Formula I is a charge carrier transportingmaterial in the organic layer.

In some embodiments, the first organic light emitting device isincorporated into a device selected from the group consisting of aconsumer product, an electronic component module, an organiclight-emitting device, and a lighting panel.

In some embodiments, the organic layer is an emissive layer and thecompound having structure according to Formula I is a first lightemitting compound. In some such embodiments, the first organic lightemitting device emits a luminescent radiation at room temperature when avoltage is applied across the organic light emitting device, and theluminescent radiation comprises a delayed fluorescence process. In somesuch embodiments, the emissive layer further comprises a firstphosphorescent emitting material. In some such embodiments, the emissivelayer further comprises a second phosphorescent emitting material. Insome such embodiments, the emissive layer further comprises a hostmaterial.

In some embodiments, where the compound of Formula I is a first lightemitting compound, the first organic light emitting device emits a whitelight at room temperature when a voltage is applied across the organiclight emitting device. In some such embodiments, the first lightemitting compound emits a blue light with a peak wavelength of about 400nm to about 500 nm, while the first light emitting compound emits ayellow light with a peak wavelength of about 530 nm to about 580 nm inother embodiments. In some embodiments, a second organic light emittingdevice can be stacked on the first organic light emitting device.

The OLED can be incorporated into one or more of a consumer product, anelectronic component module, and a lighting panel.

In yet another aspect of the present disclosure, a formulation thatcomprises the first compound of the present disclosure is described. Theformulation can include one or more components selected from the groupconsisting of a solvent, a host, a hole injection material, holetransport material, and an electron transport layer material, disclosedherein.

Combination with Other Materials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

Conductivity Dopants:

A charge transport layer can be doped with conductivity dopants tosubstantially alter its density of charge carriers, which will in turnalter its conductivity. The conductivity is increased by generatingcharge carriers in the matrix material, and depending on the type ofdopant, a change in the Fermi level of the semiconductor may also beachieved. Hole-transporting layer can be doped by p-type conductivitydopants and n-type conductivity dopants are used in theelectron-transporting layer.

Non-limiting examples of the conductivity dopants that may be used in anOLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:EP01617493, EP01968131, EP2020694, EP2684932, US20050139810,US20070160905, US20090167167, US2010288362, WO006081780, WO2009003455,WO2009008277, WO2009011327, WO2014009310, US2007252140, US2015060804 andUS2012146012.

HIL/HTL:

A hole injecting/transporting material to be used in the presentinvention is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial. Examples of the material include, but are not limited to: aphthalocyanine or porphyrin derivative; an aromatic amine derivative; anindolocarbazole derivative; a polymer containing fluorohydrocarbon; apolymer with conductivity dopants; a conducting polymer, such asPEDOT/PSS; a self-assembly monomer derived from compounds such asphosphonic acid and silane derivatives; a metal oxide derivative, suchas MoOx; a p-type semiconducting organic compound, such as1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and across-linkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, butare not limited to the following general structures:

Each of Ar¹ to Ar⁹ is selected from the group consisting of aromatichydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl,triphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, and azulene; the group consistingof aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and the group consisting of 2 to 10 cyclic structural units which aregroups of the same type or different types selected from the aromatichydrocarbon cyclic group and the aromatic heterocyclic group and arebonded to each other directly or via at least one of oxygen atom,nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom,chain structural unit and the aliphatic cyclic group. Each Ar may beunsubstituted or may be substituted by a substituent selected from thegroup consisting of deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof.

In one aspect, Ar¹ to Ar⁹ is independently selected from the groupconsisting of:

wherein k is an integer from 1 to 20; X¹⁰¹ to X¹⁰⁸ is C (including CH)or N; Z¹⁰¹ is NAr¹, O, or S; Ar¹ has the same group defined above.

Examples of metal complexes used in HIL or HTL include, but are notlimited to the following general formula:

wherein Met is a metal, which can have an atomic weight greater than 40;(Y¹⁰¹-Y¹⁰²) is a bidentate ligand, Y¹⁰¹ and Y¹⁰² are independentlyselected from C, N, O, P, and S; L¹⁰¹ is an ancillary ligand; k′ is aninteger value from 1 to the maximum number of ligands that may beattached to the metal; and k′+k″ is the maximum number of ligands thatmay be attached to the metal.

In one aspect, (Y¹⁰¹-Y¹⁰²) is a 2-phenylpyridine derivative. In anotheraspect, (Y¹⁰¹-Y¹⁰²) is a carbene ligand. In another aspect, Met isselected from Ir, Pt, Os, and Zn. In a further aspect, the metal complexhas a smallest oxidation potential in solution vs. Fc⁺/Fc couple lessthan about 0.6 V.

Non-limiting examples of the HIL and HTL materials that may be used inan OLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:CN102702075, DE 102012005215, EP01624500, EP01698613, EP01806334,EP01930964, EP01972613, EP01997799, EP02011790, EP02055700, EP02055701,EP1725079, EP2085382, EP2660300, EP650955, JP07-073529, JP2005112765,JP2007091719, JP2008021687, JP2014-009196, KR20110088898, KR20130077473,TW201139402, U.S. Ser. No. 06/517,957, US20020158242, US20030162053,US20050123751, US20060182993, US20060240279, US20070145888,US20070181874, US20070278938, US20080014464, US20080091025,US20080106190, US20080124572. US20080145707, US20080220265,US20080233434, US20080303417, US2008107919, US20090115320,US20090167161, US2009066235, US2011007385, US20110163302, US2011240968,US2011278551, US2012205642, US2013241401, US20140117329, US2014183517,U.S. Pat. No. 5,061,569, U.S. Pat. No. 5,639,914, WO05075451,WO07125714, WO08023550, WO08023759, WO2009145016, WO2010061824,WO2011075644, WO2012177006, WO2013018530, WO2013039073, WO2013087142,WO2013118812, WO2013120577, WO2013157367, WO2013175747, WO2014002873,WO2014015935, WO2014015937, WO2014030872, WO2014030921, WO2014034791,WO2014104514, WO2014157018,

EBL:

An electron blocking layer (EBL) may be used to reduce the number ofelectrons and/or excitons that leave the emissive layer. The presence ofsuch a blocking layer in a device may result in substantially higherefficiencies, and or longer lifetime, as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the EBLmaterial has a higher LUMO (closer to the vacuum level) and/or highertriplet energy than the emitter closest to the EBL interface. In someembodiments, the EBL material has a higher LUMO (closer to the vacuumlevel) and or higher triplet energy than one or more of the hostsclosest to the EBL interface. In one aspect, the compound used in EBLcontains the same molecule or the same functional groups used as one ofthe hosts described below.

Additional Hosts:

The light emitting layer of the organic EL device of the presentinvention preferably contains at least a metal complex as light emittingdopant material, and may contain one or more additional host materialsusing the metal complex as a dopant material. Examples of the hostmaterial are not particularly limited, and any metal complexes ororganic compounds may be used as long as the triplet energy of the hostis larger than that of the dopant. Any host material may be used withany dopant so long as the triplet criteria is satisfied.

Examples of metal complexes used as host are preferred to have thefollowing general formula:

wherein Met is a metal; (Y¹⁰³-Y¹⁰⁴) is a bidentate ligand, Y¹⁰³ and Y¹⁰⁴are independently selected from C, N, O, P, and S; L¹⁰¹ is an anotherligand; k′ is an integer value from 1 to the maximum number of ligandsthat may be attached to the metal; and k′+k″ is the maximum number ofligands that may be attached to the metal.

In one aspect, the metal complexes are:

wherein (O—N) is a bidentate ligand, having metal coordinated to atoms Oand N.

In another aspect, Met is selected from Ir and Pt. In a further aspect,(Y¹⁰³-Y¹⁰⁴) is a carbene ligand.

Examples of other organic compounds used as additional host are selectedfrom the group consisting of aromatic hydrocarbon cyclic compounds suchas benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene,phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene;group consisting aromatic heterocyclic compounds such asdibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene,benzofuran, benzothiophene, benzoselenophene, carbazole,indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole,triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole,thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine,oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole,indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline,isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine,phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine,phenoxazine, benzofuropyridine, furodipyridine, benzothlenopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and group consisting 2 to 10 cyclic structural units which are groups ofthe same type or different types selected from the aromatic hydrocarboncyclic group and the aromatic heterocyclic group and are bonded to eachother directly or via at least one of oxygen atom, nitrogen atom, sulfuratom, silicon atom, phosphorus atom, boron atom, chain structural unitand the aliphatic cyclic group. Wherein each group is furthersubstituted by a substituent selected from the group consisting ofhydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrite, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

In one aspect, host compound contains at least one of the followinggroups in the molecule:

wherein R¹⁰¹ to R¹⁰⁷ is independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof, when it is aryl or heteroaryl, ithas the similar definition as Ar's mentioned above. k is an integer from0 to 20 or 1 to 20; k′″ is an integer from 0 to 20. X¹⁰¹ to X¹⁰⁸ isselected from C (including CH) or N.Z¹⁰¹ and Z¹⁰² is selected from NR¹⁰¹, O, or S.

Non-limiting examples of the additional host materials that may be usedin an OLED in combination with the host compound disclosed herein areexemplified below together with references that disclose thosematerials: EP2034538, EP2034538A, EP2757608, JP2007254297,KR20100079458, KR20120088644, KR20120129733, KR20130115564, TW201329200,US20030175553, US20050238919, US20060280965, US20090017330,US20090030202, US20090167162, US20090302743, US20090309488,US20100012931, US20100084966, US20100187984, US2010187984, US2012075273,US2012126221, US2013009543, US2013105787, US2013175519, US2014001446,US20140183503, US20140225088, US2014034914, US7154114, WO2001039234,WO2004093207, WO2005014551, WO2005089025, WO2006072002, WO2006114966,WO2007063754, WO2008056746, WO2009003898, WO2009021126, WO2009063833,WO2009066778, WO2009066779, WO2009086028, WO2010056066, WO2010107244,WO2011081423, WO2011081431, WO2011086863, WO2012128298, WO2012133644,WO2012133649, WO2013024872, WO2013035275, WO2013081315, WO2013191404,WO2014142472,

Emitter:

An emitter example is not particularly limited, and any compound may beused as long as the compound is typically used as an emitter material.Examples of suitable emitter materials include, but are not limited to,compounds which can produce emissions via phosphorescence, fluorescence,thermally activated delayed fluorescence, i.e., TADF (also referred toas B-type delayed fluorescence), triplet-triplet annihilation, orcombinations of these processes.

Non-limiting examples of the emitter materials that may be used in anOLED in combination with materials disclosed herein are exemplifiedbelow together with references that disclose those materials:CN103694277, CN1696137, EB01238981, EP01239526, EP01961743, EP1239526,EP1244155, EP1642951, EP1647554, EP1841834, EP1841834B, EP2062907,EP2730583, JP2012074444, JP2013110263, JP4478555, KR1020090133652,KR20120032054, KR20130043460, TW201332980, U.S. Ser. No. 06/699,599,U.S. Ser. No. 06/916,554, US20010019782, US20020034656, US20030068526,US20030072964, US20030138657, US20050123788, US20050244673,US2005123791, US2005260449, US20060008670, US20060065890, US20060127696,US20060134459, US20060134462, US20060202194, US20060251923,US20070034863, US20070087321, US20070103060, US20070111026,US20070190359, US20070231600, US2007034863, US2007104979, US2007104980,US2007138437, US2007224450, US2007278936, US20080020237, US20080233410,US20080261076, US20080297033, US200805851, US2008161567, US2008210930,US20090039776, US20090108737, US20090115322, US20090179555,US2009085476, US2009104472, US20100090591, US20100148663, US20100244004,US20100295032, US2010102716, US2010105902, US2010244004, US2010270916,US20110057559, US20110108822, US20110204333, US2011215710, US2011227049,US2011285275, US2012292601, US20130146848, US2013033172, US2013165653,US2013181190, US2013334521, US20140246656, US2014103305, U.S. Pat. No.6,303,238, U.S. Pat. No. 6,413,656, U.S. Pat. No. 6,653,654, U.S. Pat.No. 6,670,645, U.S. Pat. No. 6,687,266, U.S. Pat. No. 6,835,469, U.S.Pat. No. 6,921,915, U.S. Pat. No. 7,279,704, U.S. Pat. No. 7,332,232,U.S. Pat. No. 7,378,162, U.S. Pat. No. 7,534,505, U.S. Pat. No.7,675,228, U.S. Pat. No. 7,728,137, U.S. Pat. No. 7,740,957, U.S. Pat.No. 7,759,489, U.S. Pat. No. 7,951,947, U.S. Pat. No. 8,067,099, U.S.Pat. No. 8,592,586, U.S. Pat. No. 8,871,361, WO06081973, WO06121811,WO07018067, WO07108362, WO07115970, WO07115981, WO08035571,WO2002015645, WO2003040257, WO2005019373, WO2006056418, WO2008054584,WO2008078800, WO2008096609, WO2008101842, WO2009000673, WO2009050281,WO2009100991, WO2010028151, WO2010054731, WO2010086089, WO2010118029,WO2011044988, WO2011051404, WO2011107491, WO2012020327, WO2012163471,WO2013094620, WO2013107487, WO2013174471, WO2014007565, WO2014008982,WO2014023377, WO2014024131, WO2014031977, WO2014038456, WO2014112450,

HBL:

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies and/or longer lifetime as compared to a similar devicelacking a blocking layer. Also, a blocking layer may be used to confineemission to a desired region of an OLED. In some embodiments, the HBLmaterial has a lower HOMO (further from the vacuum level) and or highertriplet energy than the emitter closest to the HBL interface. In someembodiments, the HBL material has a lower HOMO (further from the vacuumlevel) and or higher triplet energy than one or more of the hostsclosest to the HBL interface.

In one aspect, compound used in HBL contains the same molecule or thesame functional groups used as host described above.

In another aspect, compound used in HBL contains at least one of thefollowing groups in the molecule:

wherein k is an integer from 1 to 20; L¹⁰¹ is an another ligand, k′ isan integer from 1 to 3.

ETL:

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In one aspect, compound used in ETL contains at least one of thefollowing groups in the molecule:

wherein R¹⁰¹ is selected from the group consisting of hydrogen,deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof, when it is aryl or heteroaryl, it has the similar definition asAr's mentioned above. Ar¹ to Ar³ has the similar definition as Ar'smentioned above. k is an integer from 1 to 20. X¹⁰¹ to X¹⁰⁸ is selectedfrom C (including CH) or N.

In another aspect, the metal complexes used in ETL include, but are notlimited to the following general formula:

wherein (O—N) or (N—N) is a bidentate ligand, having metal coordinatedto atoms O, N or N, N; L¹⁰¹ is another ligand; k′ is an integer valuefrom 1 to the maximum number of ligands that may be attached to themetal.

Non-limiting examples of the ETL materials that may be used in an OLEDin combination with materials disclosed herein are exemplified belowtogether with references that disclose those materials: CN103508940,EP01602648, EP01734038, EP01956007, JP2004-022334, JP2005149918,JP2005-268199, KR01117693, KR20130108183, US20040036077, US20070104977,US2007018155, US20090101870, US20090115316, US20090140637,US20090179554, US2009218940, US2010108990, US2011156017, US2011210320,US2012193612, US2012214993, US2014014925, US2014014927, US20140284580,U.S. Pat. No. 6,656,612, U.S. Pat. No. 8,415,031, WO2003060956,WO2007111263, WO2009148269, WO2010067894, WO2010072300, WO2011074770,WO2011105373, WO2013079217, WO2013145667, WO2013180376, WO2014104499,WO2014104535,

Charge Generation Layer (CGL)

In tandem or stacked OLEDs, the CGL plays an essential role in theperformance, which is composed of an n-doped layer and a p-doped layerfor injection of electrons and holes, respectively. Electrons and holesare supplied from the CGL and electrodes. The consumed electrons andholes in the CGL are refilled by the electrons and holes injected fromthe cathode and anode, respectively; then, the bipolar currents reach asteady state gradually. Typical CGL materials include n and pconductivity dopants used in the transport layers.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated. Thus, anyspecifically listed substituent, such as, without limitation, methyl,phenyl, pyridyl, etc. encompasses undeuterated, partially deuterated,and fully deuterated versions thereof. Similarly, classes ofsubstituents such as, without limitation, alkyl, aryl, cycloalkyl,heteroaryl, etc. also encompass undeuterated, partially deuterated, andfully deuterated versions thereof.

EXPERIMENTAL Synthesis of Tetrabenzoazonine Synthesis of2′-bromo-[1,1′-biphenyl]-2-amine

A dimethylacetamide (DMA) (150 mL) and water (75 mL) mixture was bubbledwith nitrogen gas for 15 min., followed by an addition of 2-iodoaniline(10.0 g, 45.7 mmol), (2-bromophenyl)boronic acid (13.7 g, 68.5 mmol),sodium bicarbonate (15.3 g, 182.6 mmol), andtetrakis(triphenylphosphine)palladium(0) (2.6 g, 2.3 mmol). Theresulting mixture was bubbled with nitrogen gas for 15 min. and refluxedfor 18 hours. After cooling (˜22° C.), the reaction mixture was filteredthrough a silica pad and washed with dichloromethane (DCM). The solventwas removed in vacuo and the residue was purified by flash columnchromatography using 10% ethyl acetate (EA) in hexane to afford2′-bromo-[1,1′-biphenyl]-2-amine (7.3 g, 64% yield) as yellow oil.

Synthesis of N-([1,1′-biphenyl]-2-yl)-2′-bromo-[1,1′-biphenyl]-2-amine

Toluene (100 mL) was bubbled with nitrogen gas for 15 min., followed byan addition of triphenylphosphine (1.1 g, 4.0 mmol) and palladiumacetate (226 mg, 1.0 mmol). The resulting mixture was bubbled withnitrogen gas for 15 min., then 2′-bromo-[1,1′-biphenyl]-2-amine (2.5 g,10.1 mmol), 2-iodo-1,1′-biphenyl (4.2 g, 15.1 mmol), and sodiumtert-butoxide (1.5 g, 15.1 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed in vacuo and the residuewas purified by flash column chromatography using 10% DCM in hexane toafford N-([1,1′-biphenyl]-2-yl)-2′-bromo-[1,1′-biphenyl]-2-amine (2.4 g,60% yield) as colorless oil.

Synthesis of5-(2′-bromo-[1,1′-biphenyl]-2-yl)dibenzo[c,e][1,2]azaborinin-6(5H)-ol

1,2-Dichlorobenzene (7 mL) was bubbled with nitrogen gas for 15 min.,followed by an addition ofN-([1,1′-biphenyl]-2-yl)-2′-bromo-[1,1′-biphenyl]-2-amine (761 mg, 1.9mmol). The resulting mixture was bubbled with nitrogen gas for 15 min.,then boron tribromide (BBr₃) (IM solution in DCM, 2.1 m, 2.1 mmol) wasadded and the mixture was heated to reflux for 18 hours. After cooling(˜22° C.), the reaction mixture was concentrated in vacuo. The residuewas purified by flash column chromatography using 20-40% DCM in hexaneto 5-(2′-bromo-[1,1′-biphenyl]-2-yl)dibenzo[c,e][1,2]azaborinin-6(5H)-ol(577 mg, 71% yield) as a white powder.

Synthesis of 9H-tetrabenzo[b,d,f,h]azonine

A dimethoxyethane (DME) (12 mL) and water (4 mL) mixture was bubbledwith nitrogen gas for 30 min., followed by an addition oftetrakis(triphenylphosphine)palladium(0) (29 mg, 0.025 mmol). Theresulting mixture was bubbled with nitrogen gas for 15 min., then5-(2′-bromo-[1,1′-biphenyl]-2-yl)dibenzo[c,e][1,2]azaborinin-6(5H)-ol(185 mg, 0.43 mmol) and K₂CO₃ (150 mg, 1.1 mmol) were added. The mixturewas bubbled with nitrogen gas for 15 min. and refluxed for 18 hours.After cooling (˜22° C.), the reaction mixture was extracted by DCM. Theextracts were dried over MgSO₄ and the solvent was removed in vacuo. Theresidue was purified by flash column chromatography using 5-10% DCM inhexane (containing 0.25% triethylamine) to afford9H-tetrabenzo[b,d,f,h]azonine (52 mg, 38% yield) as a white solid.

Synthesis of Compound III-a-1

o-Xylene (3 mL) was bubbled with nitrogen gas for 10 min., followed byan addition of tris(dibenzylideneacetone)dipalladium(0) (Pd₂(dba)₃) (29mg, 0.031 mmol) and 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (514mg, 0.13 mmol). The resulting mixture was bubbled with nitrogen gas for15 min., then 9H-tetrabenzo[b,d,f,h]azonine (100 mg, 0.31 mmol),iodobenzene (256 mg, 1.3 mmol), and sodium tert-butoxide (451 mg, 0.47mmol) were added. The mixture was bubbled with nitrogen gas for 15 min.and refluxed for 18 hours. After cooling (˜22° C.), the reaction mixturewas filtered through a silica pad and washed with toluene. The solventwas removed in vacuo and the residue was purified by flash columnchromatography using hexane to 10% DCM in hexane to afford CompoundIII-a-1 (55 mg, 44% yield) as a white solid.

Synthesis of Compound III-a-5

o-Xylene (40 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of Pd₂(dba)₃ (2.2 g, 2.3 mmol) and tri-ter-butylphosphine(1.9 g, 9.4 mmol). The resulting mixture was bubbled with nitrogen gasfor 15 min., then 9H-tetrabenzo[b,d,f,h]azonine (2.5 g, 7.8 mmol),3-iodo-9-phenyl-9H-carbazole (5.8 g, 15.7 mmol), and sodiumtert-butoxide (978 mg, 10.2 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed in vacuo and the residuewas purified by flash column chromatography using hexane to 30% DCM inhexane to afford Compound III-a-5 (2.5 g, 57% yield) as an off-whitesolid.

Synthesis of Compound III-a-21

o-Xylene (2.5 mL) was bubbled with nitrogen gas for 10 min., followed byan addition of Pd₂(dba)₃ (60 mg, 0.065 mmol), andtri-tert-butylphosphine (107 mg, 0.26 mmol). The resulting mixture wasbubbled with nitrogen gas for 15 min., then9H-tetrabenzo[b,d,f,h]azonine (250 mg, 0.78 mmol), 2-bromotetraphenylene(100 mg, 0.26 mmol), and sodium ten-butoxide (63 mg. 0.65 mmol) wereadded. The mixture was bubbled with nitrogen gas for 15 min. andrefluxed for 18 hours. After cooling, the reaction mixture was filteredthrough a silica pad and washed with toluene. The solvent was removed invacuo and the residue was purified by flash column chromatography usinghexane to 30% DCM in hexane to afford Compound III-a-21 as an off-whitesolid.

Synthesis of 9-(3-iodophenyl)-9H-carbazole

m-Xylene (250 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of 1,3-diiodobenzene (19.7 g, 59.8 mmol), carbazole (5.0 g,29.9 mmol), potassium carbonate (20.7 g, 150.0 mmol), 18-crown-6 (7.9 g,29.9 mmol), and copper (1.9 g, 29.9 mmol). The resulting mixture wasbubbled with nitrogen gas for 15 min. and refluxed for 18 hours. Aftercooling (˜22° C.), the reaction mixture was filtered through a silicapad and washed with toluene. The solvent was removed in vacuo and theresidue was purified by flash column chromatography using hexane to DCMto afford 9-(3-iodophenyl)-9H-carbazole (5.7 g, 52% yield) as anoff-white solid.

Synthesis of Compound III-a-22

o-Xylene (35 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of Pd₂(dba)₃ (602 mg, 0.66 mmol) and2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (1.2 g, 2.6 mmol).The resulting mixture was bubbled with nitrogen gas for 15 min., then9H-tetrabenzo[b,d,f,h]azonine (2.1 g, 6.6 mmol),9-(3-iodophenyl)-9H-carbazole (3.2 g, 8.6 mmol), and sodiumtert-butoxide (948 mg, 9.9 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed in vacuo and the residuewas purified by flash column chromatography using hexane to 30% DCM inhexane to afford Compound III-a-22 (1.9 g, 52% yield) as a white solid.

Synthesis of 6-bromo-9H-tetrabenzo[b,d,f,h]azonine and6,12-dibromo-9H-tetrabenzo[b,d,f,h]azonine

A mixture of 9H-tetrabenzo[b,d,f,h]azonine (4.0 g, 12.5 mmol) and2-bromocyclopentane-1,3-dione (4.4 g, 25.1 mmol) in THF (10 ml) wasstirred for 4 hours. The solvent was removed in vacuo and the residuewas partitioned between water and DCM. The organic layer was separatedand removed in vacuo and the residue was purified by flash columnchromatography using hexane to 30% DCM in hexane to afford aninseparable mixture of 6-bromo-9H-tetrabenzo[b,d,f,h]azonine and6,12-dibromo-9H-tetrabenzo[b,d,f,h]azonine (7.3 g).

Synthesis of 6-(dibenzo[b,d]furan-4-yl)-9H-tetrabenzo[b,d,f,h]azonineand 6,12-bis(dibenzo[b,d]furan-4-yl)-9H-tetrabenzo[b,d,f,h]azonine

Toluene (120 mL), ethanol (10 mL), and water (12 mL) were bubbled withnitrogen gas for 10 min., followed by the addition of Pd₂(dba)₃ (1.7 g1.8 mmol) and 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (3.0 g,7.4 mmol). The resulting mixture was bubbled with nitrogen gas for 15min., then an inseparable mixture of6-bromo-9H-tetrabenzo[b,d,f,h]azonine,6,12-dibromo-9H-tetrabenzo[b,d,f,h]azonine (7.3 g),dibenzo[b,d]furan-4-ylboronic acid (9.7 g, 45.9 mmol), and potassiumphosphate tribasic (11.7 g, 55.1 mmol) was added. The mixture wasbubbled with nitrogen gas for 15 min. and refluxed for 18 hours. Aftercooling (˜22° C.), the reaction mixture was filtered through a silicapad and washed with toluene. The solvent was removed in vacuo and theresidue was purified by flash column chromatography using hexane to 10%EA in hexane to afford6-(dibenzo[b,d]furan-4-yl)-9H-tetrabenzo[b,d,f,h]azonine (2.2 g) and6,12-bis(dibenzo[b,d]furan-4-yl)-9H-tetrabenzo[b,d,f,h]azonine (4.0 g).

Synthesis of Compound III-b-5

o-Xylene (20 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of Pd₂(dba)₃ (358 mg, 0.39 mmol) and2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (730 mg, 1.6 mmol).The resulting mixture was bubbled with nitrogen gas for 15 min., then6-(dibenzo[b,d]furan-4-yl)-9H-tetrabenzo[b,d,f,h]azonine (1.9 g, 3.9mmol), iodobenzene (3.2 g 15.7 mmol), and sodium tert-butoxide (564 mg,5.9 mmol) were added. The mixture was bubbled with nitrogen gas for 15min. and refluxed for 18 hours. After cooling (˜22° C.), the reactionmixture was filtered through a silica pad and washed with toluene. Thesolvent was removed in vacuo and the residue was purified by flashcolumn chromatography using hexane to 30% DCM in hexane to afford6-(dibenzo[b,d]furan-4-yl)-9-phenyl-9H-tetrabenzo[b,d,f,h] CompoundIII-b-5 (1.8 g, 82% yield) as a pale yellow solid.

Synthesis of Compound III-b-18

o-Xylene (40 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of Pd₂(dba)₃ (351 mg, 0.38 mmol) and2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (716 mg, 1.5 mmol).The resulting mixture was bubbled with nitrogen gas for 15 min., then6,12-bis(dibenzo[b,d]furan-4-yl)-9H-tetrabenzo[b,d,f,h]azonine (2.5 g,3.8 mmol), iodobenzene (3.1 g, 15.3 mmol), and sodium tert-butoxide (479mg, 5.0 mmol) were added. The mixture was bubbled with nitrogen gas for15 min. and refluxed for 18 hours. After cooling (˜22° C.), the reactionmixture was filtered through a silica pad and washed with toluene. Thesolvent was removed in vacuo and the residue was purified by flashcolumn chromatography using hexane to 10% EA in hexane to affordCompound III-b-18 as a pale yellow solid.

Synthesis of Compound V-31-2

o-Xylene (1.5 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (29mg, 0.061 mmol) and Pd₂(dba)₃ (14 mg, 0.15 mmol). The resulting mixturewas bubbled with nitrogen gas for 15 min., then 3-iodobenzonitrile (70mg, 0.31 mmol),6,12-bis(dibenzo[b,d]furan-4-yl)-9H-tetrabenzo[b,d,f,h]azonine (100 mg,0.15 mmol), and sodium tert-butoxide (19 mg, 0.20 mmol) were added. Themixture was bubbled with nitrogen gas for 15 min. and refluxed for 18hours. After cooling (˜22° C.), the reaction mixture was filteredthrough a silica pad and washed with toluene. The solvent was removed invacuo and the residue was purified by flash column chromatography using10-30% EA in hexane to afford Compound V-31-2 (13 mg, 11% yield) as apale yellow solid.

Synthesis of Compound V-32-1

o-Xylene (30 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (1.2g, 2.5 mmol) and Pd₂(dba)₃ (573 mg, 0.63 mmol). The resulting mixturewas bubbled with nitrogen gas for 15 min., then 3,5-diiodobenzonitrile(500 mg, 1.4 mmol), 9H-tetrabenzo[b,d,f,h]azonine (1.0 g, 3.1 mmol), andsodium tert-butoxide (451 mg, 4.7 mmol) were added. The mixture wasbubbled with nitrogen gas for 15 min. and refluxed for 18 hours. Aftercooling (˜22° C.), the reaction mixture was filtered through a silicapad and washed with toluene. The solvent was removed in vacuo and theresidue was purified by flash column chromatography using 10-30% EA inhexane to afford Compound V-32-1 (189 mg, 8% yield) as a pale yellowsolid.

Synthesis of Compound III-a-6

Toluene (100 mL) was bubbled with nitrogen gas for 15 min., followed bythe addition of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (2.1 g,5.1 mmol) and Pd₂(dba)₃ (1.1 g, 1.2 mmol). The resulting mixture wasbubbled with nitrogen gas for 15 min., then 2-iododibenzo[b,d]furan (5.3g, 18.0 mmol), 9H-tetrabenzo[b,d,f,h]azonine (4.0 g, 12.5 mmol), andsodium tert-butoxide (1.7 g, 17.7 mmol) were added. The mixture wasbubbled with nitrogen gas for 15 min. and refluxed for 18 hours. Aftercooling (˜22° C.), the reaction mixture was filtered through a silicapad and washed with toluene. The solvent was removed in vacuo and theresidue was purified by flash column chromatography using 10% DCM inhexane to afford Compound III-a-6 (4.6 g, 76% yield) as a white solid.

Synthesis of Compound III-a-23

Toluene (100 mL) was bubbled with nitrogen gas for 15 min., followed bythe addition of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (1.0 g,2.4 mmol) and Pd₂(dba)₃ (0.60 g, 0.66 mmol). The mixture was bubbledwith nitrogen gas for 15 min., then4-(3′-iodo-[1,1′-biphenyl]-3-yl)dibenzo[b,d]thiophene (4.1 g, 8.9 mmol),9H-tetrabenzo[b,d,f,h]azonine (2.0 g, 6.3 mmol), and sodiumtert-butoxide (0.80 g, 8.3 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed in vacuo and the residuewas purified by flash column chromatography using 10-20% DCM in hexaneto afford Compound III-a-23 (3.5 g. 85% yield) as a white solid.

Synthesis of Compound II-3

Toluene (60 mL) was bubbled with nitrogen gas for 15 min., followed bythe addition of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (2.0 g,4.9 mmol) and Pd₂(dba)₃ (1.1 g, 1.2 mmol). The resulting mixture wasbubbled with nitrogen gas for 15 min., then 4,4′-diiodo-1,1′-biphenyl(2.4 g, 5.9 mmol), 9H-tetrabenzo[b,d,f,h]azonine (3.8 g, 11.9 mmol), andsodium tert-butoxide (1.6 g, 16.7 mmol) were added. The mixture wasbubbled with nitrogen gas for 15 min. and refluxed for 18 hours. Aftercooling (˜22° C.), the reaction mixture was filtered through a silicapad and washed with toluene. The solvent was removed in vacuo and theresidue was purified by flash column chromatography using 10-20% DCM inhexane to afford Compound II-3 (4.5 g, 97% yield) as a white solid.

Synthesis of Compound III-a-9

Toluene (3 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (30 mg,0.073 mmol) and Pd₂(dba)₃ (20 mg, 0.022 mmol). The mixture was bubbledwith nitrogen gas for 15 min., then 4-iododibenzo[b,d]thiophene (78 mg,0.25 mmol), 91-tetrabenzo[b,d,f,h]azonine (58 mg, 0.18 mmol), and sodiumtert-butoxide (70 mg, 0.73 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed In vacuo and the residuewas purified by flash column chromatography using 10% DCM in hexane toafford Compound III-a-9 as a white solid.

Synthesis of Compound II-6

Toluene (4 mL) was bubbled with nitrogen gas for 10 min., followed by anaddition of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (66 mg, 0.16mmol) and Pd₂(dba)₃ (32 mg, 0.035 mmol). The mixture was bubbled withnitrogen gas for 15 min., then 2,8-diiododibenzo[b,d]furan (85 mg, 0.20mmol), 9H-tetrabenzo[b,d,f,h]azonine (129 mg, 0.40 mmol), and sodiumtert-butoxide (54 mg, 0.56 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed in vacuo and the residuewas purified by flash column chromatography using 10% DCM in hexane toafford Compound II-6 (187 mg, 52% yield) as a white solid.

Synthesis of Compound V-31-1

Toluene (3 mL) was bubbled with nitrogen gas for 10 min., followed by anaddition of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (43 mg, 0.11mmol) and Pd₂(dba)₃ (21 mg, 0.023 mmol). The resulting mixture wasbubbled with nitrogen gas for 15 min., then 3-iodobenzonitrile (81 mg,1.4 mmol), 9H-tetrabenzo[b,d,f,h]azonine (81 mg, 0.25 mmol), and sodiumtert-butoxide (34 mg, 0.35 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed in vacuo and the residuewas purified by flash column chromatography using 10-40% DCM in hexaneto afford Compound V-31-1 (53 mg, 50% yield) as a white solid.

Synthesis of Compound V-33-1

Toluene (3 mL) was bubbled with nitrogen gas for 10 min., followed by anaddition of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (54 mg, 0.13mmol) and Pd₂(dba)₃ (29 mg, 0.032 mmol). The mixture was bubbled withnitrogen gas for 15 min., then 4-iodobenzonitrile (106 mg, 0.46 mmol),9H-tetrabenzo[b,d,f,h]azonine (100 mg, 0.31 mmol), and sodiumtert-butoxide (42 mg, 0.44 mmol) were added. The mixture was bubbledwith nitrogen gas for 15 min. and refluxed for 18 hours. After cooling(˜22° C.), the reaction mixture was filtered through a silica pad andwashed with toluene. The solvent was removed in vacuo and the residuewas purified by flash column chromatography using 10-40% DCM in hexaneto afford Compound V-33-1 (86 mg, 65% yield) as a white solid.

Synthesis of Compound V-34-1

Toluene (3 mL) was bubbled with nitrogen gas for 10 min., followed bythe addition of 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (234mg, 0.50 mmol) and Pd₂(dba)₃ (128 mg, 0.14 mmol). The resulting mixturewas bubbled with nitrogen gas for 15 min., then 4-iodophthalonitrile(446 mg, 1.8 mmol), 9H-tetrabenzo[b,d,f,h]azonine (400 mg, 1.3 mmol),and sodium tert-butoxide (169 mg, 1.8 mmol) were added. The mixture wasbubbled with nitrogen gas for 15 min. and refluxed for 18 hours. Aftercooling (˜22° C.), the reaction mixture was filtered through a silicapad and washed with toluene. The solvent was removed in vacuo and theresidue was purified by flash column chromatography using 10-40% DCM inhexane to afford Compound V-34-1 (150 mg, 27% yield) as an off-whitesolid.

Photophysics and Electrochemistry Results

Experimentally, tetrabenzoazonine

shows singlet and triplet energy of 359 nm and 410 nm respectively,confirming the high triplet nature. Cyclic voltammetry shows E_(ox)=0.91(IR) and E_(red)=3.00 (R). Additional Photophysics and electrochemistrydata are summarized in FIG. 3.

The data in FIG. 3 shows compounds of Formula I are suitable for manyapplication in OLED. For example, Compound II-3 has HOMO/LUMO levelssuitable for use as a hole transporter. Compounds of the III-a serieshave high triplet energies and are suitable as hosts for bluephosphorescent OLED. Compounds of the III-b series have triplet energiessuitable as hosts for green and yellow phosphorescent OLED. Compounds ofthe III-a and III-b series are also suitable as charge blocking (hole orelectron blocking) layer materials. Compounds of the V series aresuitable as delayed fluorescence emitters as exemplified by the smallenergy difference between triplet and singlet, and the high PLQY frompresumably the charge transfer emission at room temperature.

DEVICE EXAMPLES

In the OLED experiment, all device examples were fabricated by highvacuum (<10⁻⁷ Torr) thermal evaporation. The anode electrode is ˜800 Åof indium tin oxide (ITO). The cathode consisted of 10 Å of LiF followedby 1,000 Å of Al. All devices were encapsulated with a glass lid sealedwith an epoxy resin in a nitrogen glove box (<1 ppm of H₂O and O₂) and amoisture getter was incorporated inside the package.

Device Example 1

The organic stack of the Device Examples in Table I consists ofsequentially, from the ITO surface, 100 Å of LG101 (purchased from L.GChem, Korea) as the hole injection layer (HIL), 250 Å of Compound A thehole transport layer (HTL), 50 Å of Compound III-a-5 as the secondaryhole transport layer (also known as electron blocking layer), 300 Å ofCompound B doped with 20% of the emitter Compound C as the emissivelayer (EML), 50 Å of Compound B as ETL2 and 300 Å of Alq₃ as ETL1. At1000 cd/m², the device efficiency was 17% EQE with CIE of 0.169, 0.387.The result demonstrated that Compounds of Formula I are suitable forOLED applications.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

1. A compound having a structure of Formula I:

wherein each one of X¹ to X¹⁶ is independently CR^(X) or N; wherein eachR^(X) and R are independently selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole,azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene,azadibenzofuran, azadibenzothiophene, azadibenzoselenophene,triphenylene, azatriphenylene, and combinations thereof; and wherein anyadjacent R^(X) can join to form fused or unfused rings.
 2. The compoundof claim 1, having the structure of Formula I-a:

wherein each one of R¹ to R¹⁶ independently represents a substituentselected from the group consisting of hydrogen, deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof, wherein any adjacent R¹-R¹⁶can join to form a fused or unfused ring.
 3. The compound of claim 2,having the structure of Formula II:

wherein n is an integer≧1; wherein R^(t) is

wherein all rings are optionally independently substituted by asubstituent selected from the group consisting of deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; and wherein any adjacentsubstituents can join to form fused or unfused rings.
 4. (canceled) 5.The compound of claim 2, wherein R is selected from the group consistingof aryl, heteroaryl, substituted aryl, and substituted heteroaryl. 6.(canceled)
 7. The compound of claim 2, wherein at least one of R¹ to R¹⁶is selected from the group consisting of aryl, heteroaryl, substitutedaryl, and substituted heteroaryl.
 8. (canceled)
 9. The compound of claim2, wherein R is a triarylamine containing group.
 10. (canceled)
 11. Thecompound of claim 2, wherein R is a group containing at least oneelectron withdrawing group of CN, F, C_(m)F_(2m+1), Si_(m)F_(2m+1), NCO,NCS, OCN, SCN, OC_(m)F_(2m+1), or SC_(m)F_(2m+1), wherein m≧1.
 12. Thecompound of claim 11, wherein the compound is selected from the groupconsisting of:

wherein R^(e) is CN, F, C_(m)F_(2m+1), Si_(m)F_(2m+1), NCO, NCS, OCN,SCN, OC_(m)F_(2m+1), or SC_(m)F_(2m+1), and m≧1; and wherein R^(t) is

wherein all rings of R^(t) are optionally independently substituted by asubstituent selected from the group consisting of deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; and wherein any adjacentsubstituents on R^(t) can join to form fused or unfused rings.
 13. Thecompound of claim 2, wherein R is a group containing pyrimidine ortriazene.
 14. (canceled)
 15. The compound of claim 1, wherein at leastone of X¹ to X¹⁶ is N.
 16. (canceled)
 17. The compound of claim 1,wherein at least two of adjacent R¹-R¹⁶ are fused into

wherein Z is CR′R″, NR′, O, S, or Se; wherein R′ and R″ areindependently selected from the group consisting of hydrogen, deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole,azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene,azadibenzofuran, azadibenzothiophene, azadibenzoselenophene,triphenylene, azatriphenylene, and combinations thereof; and wherein allof the rings are optionally substituted.
 18. (canceled)
 19. A firstorganic light emitting device comprising: an anode; a cathode; and anorganic layer, disposed between the anode and the cathode, comprising acompound having a structure of Formula I:

wherein each one of X¹ to X¹⁶ is independently CR^(X) or N; whereinR^(X) and R are independently selected from the group consisting ofhydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, carbazole,azacarbazole, dibenzofuran, dibenzothiophene, dibenzoselenophene,azadibenzofuran, azadibenzothiophene, azadibenzoselenophene,triphenylene, azatriphenylene, and combinations thereof; and wherein anyadjacent R^(X) can join to form fused or unfused rings.
 20. The firstorganic light emitting device of claim 19, wherein the organic layer isan emissive layer and the compound of Formula I is a host.
 21. The firstorganic light emitting device of claim 19, wherein the organic layerfurther comprises a phosphorescent emissive dopant wherein thephosphorescent emissive dopant is a transition metal complex having atleast one ligand or part of the ligand if the ligand is more thanbidentate, selected from the group consisting of:

wherein each X¹ to X¹³ are independently selected from the groupconsisting of carbon and nitrogen; wherein X is selected from the groupconsisting of BR′, NR′, PR′, O, S, Se, C═O, S═O, SO₂, CR′R″, SiR′R″, andGeR′R″; wherein R′ and R″ are optionally fused or joined to form a ring;wherein each R_(a), R_(b), R_(c), and R_(d) may represent from monosubstitution to the possible maximum number of substitution, or nosubstitution; wherein R′, R″, R_(a), R_(b), R_(c), and R_(d) are eachindependently selected from the group consisting of hydrogen, deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof; and wherein any two adjacent substituents of R_(a), R_(b),R_(c), and R_(d) are optionally fused or joined to form a ring or form amultidentate ligand.
 22. (canceled)
 23. (canceled)
 24. The first organiclight emitting device of claim 19, wherein the organic light emittingdevice is incorporated into a device selected from the group consistingof a consumer product, an electronic component module, an organiclight-emitting device, and a lighting panel.
 25. The first organic lightemitting device of claim 19, wherein the organic layer is an emissivelayer and the compound having structure according to Formula I is afirst light emitting compound.
 26. The first organic light emittingdevice of claim 25, wherein the first organic light emitting deviceemits a luminescent radiation at room temperature when a voltage isapplied across the organic light emitting device; and wherein theluminescent radiation comprises a delayed fluorescence process. 27.-33.(canceled)
 34. The compound of claim 1, wherein the compound is selectedfrom the group consisting of:

wherein all of the rings are optionally substituted, and

wherein R^(t) is

wherein all rings of R^(t) are optionally independently substituted by asubstituent selected from the group consisting of deuterium, halogen,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, carbazole, azacarbazole, dibenzofuran,dibenzothiophene, dibenzoselenophene, azadibenzofuran,azadibenzothiophene, azadibenzoselenophene, triphenylene,azatriphenylene, and combinations thereof; and wherein any adjacentsubstituents on R^(t) can join to form fused or unfused rings.
 35. Thecompound of claim 15, wherein the compound is selected from the groupconsisting of:

wherein all of the rings are optionally substituted.